Optimal power collection control method and apparatus in solar photovoltaic power generation system

Abstract

A control apparatus controls an optimizer that steps up a DC input voltage from a solar photovoltaic power generation panel to a predetermined DC high voltage and converts the stepped-up DC voltage into a grid connection voltage, and includes a microprocessor; a sensor group; and a MOS driver group. The microprocessor includes: a control logic unit; a maximum power point tracking control unit; a PWM control unit; a PFM control unit; an I / O port; a timer control unit; and an initial measurement unit. The sensor group includes a solar photovoltaic panel voltage detection circuit; a solar photovoltaic panel current detection circuit; an optimizer output voltage detection circuit; and an optimizer output current detection unit. Thus, even when the solar photovoltaic power generation panel is at a low power in a low output state, stable operation can be continued, and transistors can be protected from a surge voltage.

Description

RELATED APPLICATIONS[0001]The present application is National Phase of International Application No. PCT / JP2015 / 073833 filed Aug. 25, 2015, and claims priority from Japanese Application No. 2014-181499, filed Sep. 5, 2014, the disclosure of which is hereby incorporated by reference herein in its entirety.TECHNICAL FIELD[0002]The present invention relates to a power generation system through use of a solar photovoltaic panel and, in particular, to an optimal power collection control method and apparatus in a solar photovoltaic power generation system that can stably harvest generated power by optimizing power output from a solar photovoltaic panel with large output variation.BACKGROUND ART[0003]Along with diversification of energy resources, power generation through use of a solar photovoltaic panel has become widespread as a type of renewable energy. Against the backdrop of lack of energy sources and reduction in CO2 emission in recent years, large-scale solar photovoltaic power gen...

AI Technical Summary

Benefits of technology

[0085]According to the optimal power collection control apparatus in the solar photovoltaic power generation system of the present invention, in the case where the DC input power from the solar photovoltaic panel is smaller than the predetermined value, the stepping-up is controlled through pulse frequency modulation control (PFM) (execution of the first control mode). In the case where the DC input power from the solar photovoltaic panel is at least the predetermined value, it is determined that increase in the power output of the solar photovoltaic panel causes the limit of control in the first control mode to be reached, the stepping-up is controlled through the pulse width modulation control (PWM) (execution of the second control mode). Such control of switching the operation of the optimizer between the first control mode and the second control mode according to the magnitude of the DC input power from the solar photovoltaic panel can particularly stabilize the operation at a DC input power from the solar photovoltaic panel, the power being a low power lower than a predetermined value, and perform stable operation of the entire system even with variation in optical energy with which the solar photovoltaic panel is irradiated.

[0086]The solar photovoltaic output optimizer used for the present invention can prevent the surge voltage from occurring by the operation of the protection circuit provided for the input circuit, prevent breakage of the switching transistors, and achieve stable operation even with variation in the output of the PV panel.

Problems solved by technology

Connection of a load in a state with a high internal impedance reduces the voltage, which prevents normal operation as a power source, and the power source becomes an unstable power source.

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